'non-reinforced' is formed from the prefix 'non-' and the adjective 'reinforced'. 'non-' originates from Latin 'non', meaning 'not'; 'reinforced' comes from Old French/French 'renforcer' (see 'reinforce'), where 're-' meant 'again' and the root related to Latin 'fortis' (strong).

'reinforce' came into English via Old French (renforcier / renforcer) meaning 'make strong again'; English formed 'reinforced' as the past/adjective form, and then the negative prefix 'non-' was attached in modern English to create 'non-reinforced'.

Initially components conveyed 'not' + 'made strong again'; in modern technical usage it specifically denotes materials or structures that have not been provided with reinforcement (for example, lacking steel reinforcement).